[Issue 1826] TransitiveBaseTypeTuple skips interfaces implemented by base types

[Christopher Wright]

> ------- Comment #1 from andrei at metalanguage.com  2008-02-09 11:08 -------
> That was pretty silly of me; thanks for the report. I fixed the bug by adding
> InterfacesTuple!(T) to return all interfaces directly or indirectly inherited
> by T (without duplicates), and by using that in TransitiveBaseTypesTuple!(T).
> In case you are in a hurry, I paste the two templates (the new one and the
> modified one) below.

Thanks! I'm not in a hurry, really -- since Tango doesn't have the 
equivalent, I'm implementing it anyway.